Improvement of the Nursery Upweller for Young Oysters in Tropical Mangrove Estuaries

Abstract

To streamline oyster aquaculture practices, a compact nursery upweller system for young oysters was developed using commercially available components, based on the principles of conventional forced flow upweller designs. A field experiment was conducted at a commercial oyster farm to evaluate the system’s performance. Young oysters were reared in the improved device, and two control groups were established for comparison: one utilising net cages alone, and another employing net cages with aeration. Growth conditions among the groups were systematically assessed. The experimental results revealed that the improved upweller device significantly enhanced the accumulation of phytopigments in the digestive gland tissue, which was associated with more distinct shell edge formation in a substantial number of individuals. Quantitative analysis of shell length and morphological characteristics indicated a significant promotion of growth in oysters cultured within the device. Although routine cleaning—at least once per week—is necessary in mangrove brackish water environments, the simplified structural design of the device contributes to improved operational efficiency. This integrated and accessible design enables oyster farmers to independently assemble, install, and maintain the system on-site, thereby reducing labour demands and facilitating broader adoption in small-scale aquaculture operations.

Keywords

• Oyster
• nursery upweller
• phytopigments
• growth promotion
• mangrove estuary

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